I've been over most of Europe and the friendliest place I've been is Mexico.
One time I got off the bus in Puerta Vallarta and was carrying two large bags. (I had accumulated a lot of junk over my 3 months there.) Some guy came up and offered to help me carry them. I thought to myself this might be a trick, but at least he won't be running too fast if he is carrying my bag. I should be able to catch him easily. And if he was going to threaten me with a weapon then it doesn't matter if he is carrying my bag anyway. So I agreed to let him help.
I was looking to take a boat to an isolated community. He told me that the dock on the beach where I was had already finished it's last run for the day. It was early afternoon at the time, but it isn't like the US where things are open 24/7. He said there was another place that still has a boat running. So we got on the bus and went for a 15 minute ride out of the downtown area. At this point I'm starting to think I'm pretty stupid.
We get off at this little restaurant with a nearby dock. The next boat is ready to leave in about 30 minutes. I see other foreigners there arranging there belongings on the boat. I start to feel safer. I offer to buy this helpful guy some lunch, and we sit down and talk for a short time. This is where he tells me that he was planning to rob me. Then he gives me the name of someone in the area that I'm going to that can hook me up with a place to stay for the time I'm there. (oh, he asked for a few bucks also, which I gladly gave him. He earned it.)
See? Even the criminals are polite!
I ran into the guy that he recommended. He was wealking on the beach selling pot from a fat log that he carried around in his hand. There was no authority at this location. He was also sleazing my friend's sister persistently. Even despite these things I wouldn't have trusted this guy. I got bad vibes from him.